Conventionally, industrial mixing devices have been permanently located. Utilization of such equipment has accordingly required that material to be mixed or blended to transported to the mixing devices, removed from one or more storage containers, inserted into the mixing devices, mixed or blended, removed from the mixing devices and placed inside new storage or shipping containers. Of course, the mixing devices must be cleaned periodically and normally after every batch operation. These various operations obviously require considerable time and labor in addition to creating storage problems for containers. Completely automated systems for batch type operations can be devised but tend to be somewhat rare. Not only are automated systems costly, but such automation tends to defeat flexibility -- an inherent advantage of batch operations.
In addition to the time and expense involved with materials handling aspects of batch type operations, the problem of contamination and pollution control are very significant. In industries such as the pharmaceutical industry and food industry product purity is synonymous with product quality. The very real and serious hazards which can occur by cross contamination of pharmaceutical ingredients have led the Food and Drug Administration of the U.S. Government to require very rigid housekeeping efforts to eliminate contamination problems. This has meant that equipment such as mixing equipment which is used to perform its function with a variety of product formulations must be cleaned laboriously between runs of different material. The problem, however, involves more than simply the time consuming effort required to clean previously used containers and mixing equipment. Part of the existing problem is the exposure of material to the plant environment, including solid materials and vapors, and the effort required to prevent migration of material either into the plant environment or of impurities into the material from the plant environment. Environment control is exceedingly difficult when material is being transferred back and forth between containers and processing equipment. The solutions which have been suggested for combating problems of contamination and environmental pollution, including such practices as segregation of different product operations, utilization of vacuum systems to combat dust problems, and the like, all have recognized limitations.
Included among the various devices and procedures which have been proposed for handling both solid and liquid materials in an attempt to obtain improved handling procedures are those proposed by Schmidt and Wheeler. U.S. Pat. No. 3,315,945, to Alfred Schmidt, as well as U.S. Pat. No. 4,090,604, to Delbert Wheeler, involve equipment designed to be used in conjunction with a standard 55 gallon metal drum for mixing the contents of the drum. According to the Schmidt patent, the metal drum must be clamped to a circular frame which is then rotated in order to accomplish some form of mixing. The Wheeler patent also involves means for securing a metal drum to a frame which is then moved to accomplish some form of mixing action. The objective in both the Schmidt and Wheeler patents is to position a standard industrial drum at an angle which will promote efficient mixing of the container contents. Movement of a 55 gallon industrial drum containing granular powder or liquid material, however, can be very difficult even with leverage applied to the drum. There is simply no convenient or quick way of mounting a 55 gallon industrial drum in the apparatus taught by Schmidt and Wheeler or convenient or quick way of introducing variations in drum size.
Suppliers of specialized storage containers have also offered some improvement in the materials handling aspects of batch processing apparatus. Today portable bins of various kinds are frequently employed for charging and discharging process machines, transferring materials between processing machines and storing materials, including the raw materials, intermediates and final product. In reality, such bins are simply glorified versions of the standard 55 gallon metal drum which has conventionally been used in industry for storing and shipping liquids and dry bulk material. For convenience, the portable bins are normally equipped with resealable openings, piping to facilitate removal of contents, and corner extensions which permit stacking the bins during shipment or storage. Notwithstanding the use of specially designed storage containers, charging and discharging the containers remains time consuming, costly, dirty and troublesome and it has been almost impossible in batch type operations to approximate the coordination of storage, movement and processing that is taken for granted in continuous operations.
Another approach which has been proposed in order to reduce capital equipment costs and improve overall efficiency has been to employ multiple cone blenders in conjunction with one drive unit. Use of cone type hoppers which can be bolted one at a time to a single drive unit has helped to reduce capital investment costs in some operations, but has not overcome contamination, storage, transfer, interplant shipment and cleaning problems. Of course, the drive unit can only be used with a fixed hopper size.
Process container apparatus and a system have now been developed which provide clean, safe, economical and flexible materials handling for bath type operations. By improving the materials handling aspects of batch operations the efficiency of an entire manufacturing operation can be improved.